1. Field of the Invention
The invention relates to the field of additives for fuel dehydration, and more specifically, to additives for dehazing crude oil distillates and demulsifying separated water emulsions.
2. Description of the Prior Art
Detergents are often added to gasoline to improve engine performance and prevent fouling and deposits. These hydrophilic compounds sometimes serve to disperse water into the gasoline. Additives are therefore needed for water removal. In addition, the separated water may be emulsified (rather than exist as "free" water). Chemicals which dehaze petroleum fuel and demulsify separated water emulsions include phenolic resin alkoxylates, polyethers, hydroxylated resin acids.
SUMMARY OF THE INVENTION
The present invention deals with a new class of additives which dehaze or dewater gasoline and crude oil distillates. These novel additives are vinyl polymers made from one or more hydrophilic monomers and one or more hydrophobic monomers. For discussion purposes, the term "hydrophilic" refers to monomers for which the weight percent of heteroatoms (e.g., oxygen, nitrogen) is greater than or equal to about 27, and the term "hydrophobic" refers to monomers for which the weight percent of heteroatoms is less than about 27.
Effective polymers are found within a wide range of hydrophilic/hydrophobic weight ratios. Especially efficacious are those polymers with overall hydrophilic/hydrophobic weight ratios of 65/35 to 35/65, and polymers for which the overall weight percent of heteroatoms ranges from about 25.5 to 27.5.